CCI Solar Events - February, 2018

Bulk Powders and Single Crystals for Identifying New HER and OER Catalysts

As part of our ongoing research to identify and characterize new heterogeneous catalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in acidic electrolytes, we have been targeting compounds that are not readily accessible using synthetic strategies typically employed for catalyst discovery efforts.

In this talk, we will present two systems where techniques from high-temperature solid-state synthesis have provided access to refractory compounds that are candidate materials for HER and OER catalysis.

First, we will expand on previous work indicating that compounds combining 3d transition metals with Ta and Sb, synthesized using arc-melting and powder metallurgy techniques, are promising candidates for acid-stable water oxidation catalysts.

Second, we have found that millimeter-scale MoAlB single crystals grown in a high-temperature molten aluminum flux are active HER catalysts. MoAlB is a layered compound, and the single crystals enable facet-selective characterization of the catalytic properties. We will also present preliminary results of studies aimed at generating nanostructured MoAlB via selective etching of Al, which helps to bridge the gap between bulk materials and their higher surface area nanostructured analogues.